William Henry Pratt (23 November 1887 – 2 February 1969), better known by his stage name Boris Karloff (), was an English actor who was primarily known for his roles in horror films. He portrayed Frankenstein's monster in Frankenstein (1931), Bride of Frankenstein (1935) and Son of Frankenstein (1939). He also appeared as Imhotep in The Mummy (1932).

His best-known non-horror role is as the Grinch, as well as the narrator, in the animated television special of Dr. Seuss' How the Grinch Stole Christmas! (1966). For his contribution to film and television, Boris Karloff was awarded two stars on the Hollywood Walk of Fame.